The asymmetric unit of the title compound, C20H24N2, contains one half -molecule which exhibits a crystallographically imposed center of symmetry. The benzene rings are inclined to the 1,4-diazabutadiene mean plane by 78.3 (2)°.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: CV5204 ).

Acknowledgements

We thank the National Natural Science Foundation of China (grant No. 20964003) for funding. We also thank the Key Laboratory of Eco Environment-Related Polymer Materials of the Ministry of Education and Key Laboratory of Polymer Materials of Gansu Province (Northwest Normal University) for financial support.

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